Tire construction employing novel reinforcing system



I ..I\I

Arrow/E KS March 28, 1967 3,311,152

TIRE CONSTRUCTION EMPLOYING NOVEL REINFORCING SYSTEM A. MARZOCCHI ETAL 6Sheets-Sheet 2 Filed April 50, 1965 INVENTORS ALFRED MARZOCQH! BY FRANKas. LAQHOT M QM.

ATTORNEYS March 28, 1967 A. MARZOCCHI ETAL 3,311,152

TIRE CONSTRUCTION EMPLOYING NOVEL REINFORCING SYSTEM 6 Sheets-Sheet 3Filed April 30, 1965 v w? 5 TO H v NZC E R A N AL a N 0 .v T A W March28, 1967 A. MARZOCCHI ETAL 3,311,152

TIRE CONSTRUCTION EMPLOYING NOVEL REINFORCING SYSTEM Filed April 30,1965 6 Sheets-Sheet 5 INVENTORS ALFRED MARZOCCHI FRAN K J LACHUT A WeRNEZQS March 1967 A. MARZOCCHI ETAL 3,311,152

TIRE CONSTRUCTION EMPLOYING NOVEL REINFORCING SYSTEM 6 Sheets-Sheet 6Filed April 30, 1965 mod E QE

United States Patent 3,311,152 TIRE CGNSTRUCTION EMPLOYING NOVELREINFORCING SYSTEM Alfred Marzocchi, Cumberland, and Frank J. Lachut,Pawtucket, R.l., assignors to Owens-Coming Fiberglas Corporation, acorporation of Delaware Filed Apr. 30, 1965, Ser. No. 452,096 20 Claims.(Cl. 152-359) The present invention relates to tire constructions. Moreparticularly, the present invention relates to a pneumatic tireconstruction employing a novel reinforcing system.

In conventional tire constructions, both passenger, truck andoif-the-road tires, a number of conventional fabrics have been employedas reinforcement components, usually referred to as the carcass. Thus,over the years, cotton, rayon, nylon, polyester (Dacron), and even finehigh tensile steel wire, have been employed in fabricating the carcassplies of tire constructions.

All of these aforementioned organic textiles possess certain individualproperties which have made them a desirable reinforcing component, e.g.,carcass, for tires. Glass fibers, as such, have also been suggested as acandidate reinforcing component for pneumatic tires. See, for example,Thomas U.S. Pat. No. 2,184,326.

The earliest reinforcing fabric was cotton. Cotton,

unfortunately, is subject to moisture degradation and elongation uponexposure to moisture. Rayon, on the other hand, is quite low in modulusand also possesses low strength per unit cross sectional area. Polyamidefibers, e.g., nylon, possess considerably increased strength as comparedto rayon, but unfortunately suffers undesirable elongation under load.This is usually attributed to tension stresses developed in the tireunder service conditions which, of course, cause heat build up. Thisphenomenon also causes the tire casing to increase in size which sets upstresses, causing ultimate cracks to develop in the tread, greatlyreducing of the resistance of the tread to wear. Flat spotting is alsoassociated with nylon tires and is evident in a thumping which is veryobviously noticeable to the driver of the auto on which mounted. All ofthe candidate organic fibers used to date are possessed of the commonproblem attributed to elongation in that tire produced by differentmanufacturers in different facilities are of different overalldimension.

Conventional bias type tires employing rayon or nylon carcasses are alsoknown to exhibit squirming, which is manifested in undesired treadmovement under load, particularly upon braking, cornering, acceleration,etc. This normally results in unusual tread wear and frequently in anunstable condition with respect to the gripping action of the tread uponthe road surface.

It is an object of the present invention to provide a pneumatic tireemploying a novel carcass reinforcement based upon a particular glassfiber assembly or cord and a specific arrangement thereof which togethercombine to yield a tire which is improved in almost every respect as towear, dimensional stability, general performance characteristics and,particularly, improved mileage.

It is also an object of the present invention to provide a bias-typecarcass reinforced, pneumatic tire which is eminently more stable indynamic application than tires known heretofore.

It is also an object of the present invention to provide a bias-typetire employing, in part, polyamide, e.g., nylon, carcass reinforcementin combination with assembled fibers, e.g., cords in the form of plieswhich obviate the normal difficulties normally associated inreinforcement by polyamide fibers, e.g., nylon.

Patented Mar. 28, 1967 It is additionally an object of the presentinvention to provide a radial tire featuring glass cord reinforcement inthe form of a single radial carcass ply in combination with one or morebelt or restricting plies.

It is still another object of the present invention to provide a novelreinforcing system for ready adoption in retreading operations which areof particular economic significance in the field of truck andoif-the-road tires.

It is additionally an object of the present invention to provide a tirepossessing novel reinforcement which eliminates tread squirming, therebyyielding a tire which lends to the vehicle upon mounted greaterstability, greater tire wear and greater safety under conditionsnormally involving parameters of instability.

It is likewise an object of the present invention to provide a novelreinforcing system which is adapted to be readily incorporated intoconventional tire manufacturing techniques.

It is still another object of the present invention to provide areinforcing system which lends uniformity to tire manufacturingoperations and, as well, to the ultimate tire, e.g., uniformity of tiredimension is achieved providing that the same tire specifications arefollowed and regardless of the particular tire building facilityutilized.

At the same time, it is an object of the present invention to provide atire which is improved as to dimensional stability over a period of longroad service. 7

In keeping with the just-preceding object, it is an additional object ofthe present invention to provide tire constructions which are to agreater degree utilizable for purposes of recapping; thus, increasingthe ultimate service life of the basic tire carcass.

It is also an object of the present invention to provide a novel andimproved technique for fabricating a carcass construction for apneumatic tire.

It is also an object of the present invention to provide a novel beadring construction featuring improved bead integrity and avoidance ofdistortion of the bead ring components.

It is likewise an object of the present invention to provide a tirewhich inherently possesses the ability to impress a more uniformfootprint, as it were, under varying road conditions encountered undernormal as Well as extraordinary service use.

The foregoing, as well as other and additional objects of the presentinvention, will become apparent to those skilled in the art from thefollowing more detailed description taken in conjunction with theannexed sheets of drawings on which there are presented, for purposes ofillustration only, a number of variant embodiments of (1) tireconstructions, (2) tire reinforcing components and (3) techniques ofmanufacture in accordance with the present invention.

In its simplest form, the present invention envisions a pneumatic tireconstruction composed of spaced beads, a connecting carcass and a groundengaging tread extending peripherally about the crown portion of thecarcass, in which the carcass includes, at least in part, a layercontaining a plurality of closely spaced, mutually parallel cordscomposed of a plurality of assembled strands of substantially continuousglass filaments; said layer preferably including an elastomeric matrixpreventing sub stantial contact of adjacent fibers within the cordassembly.

In the drawings:

FIG. 1 is a generally three-quarter perspective view of a section of apneumatic tire in which the outer tread and portions of the bias plycarcass components have been broken away for purposes of more clearlyshowing the interior reinforcing structure in accordance with oneembodiment of the present invention.

FIG. 2 is an elevation view of the tire shown in FIG. 1 looking at thetread head-on but with a portion of the tread as well as portions of thereinforcing plies broken away in order to better show the relativeangular disposition of the several carcass components.

FIG. 3 is a perspective view of a radial ply tire construction shown inperspective three-quarter view with a portion of the tread, side walland the carcass broken away in order to show the interior constructionaldetails in accordance with another embodiment of the present invention.

FIG. 4 is an elevation view similar to that of FIG. 2, but of the tireshown in FIG. 3.

FIG. 5 is a generally three-quarter perspective view of a radial tireconstruction embodying features of reinforoement in accordance withanother embodiment of the present invention.

FIG. 6 is an elevation view similar to FIG. 2 and FIG. 4, but of thetire shown in FIG. 5.

FIG. 7 is a top plan view of a piece of woven fabric constituting areinforcing carcass ply in accordance with the present invention.

FIG. 8 is an edge view of a tire reinforcement component representing avariant construction in accordance with the present invention.

FIG. 9 is an elevation view of a tire embodying a particularconstruction in accordance with the present invention and havingportions of the tread and of the various carcass components broken awayfor clarity of illustration.

FIG. 10 is a partial sectional view of the tire construction illustratedin FIG. 9.

FIG. 11 is a view similar to FIG. 9, but illustrating a tireconstruction representing a still further embodiment of the presentinvention.

FIG. 12 is a perspective view of a section of a tire embodying a beadconstruction in accordance with the present invention.

FIG. 13 is a schematic view illustrating a particular technique forcontinuously producing a glass-containing reinforcing component suitablefor utilization as a carcass ply or a reinforcing belt in tireconstructions in accordance with the present invention.

FIG. 14 is a schematic top plan view of the apparatus .shown in sideelevation in FIG. 13.

Tires embodying constructional features in accordance with the presentinvention exhibit extremely desirable performance characteristics underactual road tests as will become evident from the examples appearinghereinafter.

As used here, a filament of glass is meant to define an individual fiberof glass. A strand, on the other hand, is a collection of a greatplurality of individual filaments. A strand may include 104 filaments,208 filaments, and even up to 500-2000 individual filaments gatheredtogether in a manner well-known in the art and technology of glass fibermanufacture. A cord or bundle is made up of a plurality of strands,e.g., ranging from 2 to 30 and even up to 50 strands, plied or assembledtogether continuously. Strands may possess a twist, reverse twist, or notwist at all. Several different assemblies of strands may be combined toyield an ultimate cord having a total number of strands equal to thenumber of strands in the first assembly and the number of theseassemblies combined to make up the final cord. Thus, a cord may becomposed of a large number of individual filaments ranging in numberfrom 200- 30,000. By way of illustration, a cord construction mayfeature 10 strands of continuous filaments gathered together with orwithout twist. Additionally, 3 of the just foregoing mentioned 10-plystrand assemblies may be joined together with or without twist to form a30-strand assembly; each strand being composed, for example, of 100-200filaments yielding a 30006000 filament cord or bundle assembly. Thelatter is frequently designated a 10/3 cord. A 10/5/3 cord is anassembly of three In order that the glass fibers can most effectivelycontribute reinforcing action to the tire, it is desirable that theglass fibers be first treated or sized, as it were, to provide aprotection against interfilament destructive action. The latter isovercome preferably by a combination of treatments to provide aprotective coating as well as a bonding and anchoring agent on thesurface which will enhance the bonding between the glass fiber surfaceand the elastomeric material. This is usually accomplished by acombination of sprayed-on liquid size treatments just after the glassfilament is formed and a subsequent impregnation of the strands or cordsas they are formed, usually simply by introducing the gathered filamentsinto a pool of the treating liquid while simultaneously distorting thestrand filaments to effect penetration into the zones between fibers,thereby insuring complete impregnation. Following impregnation, thecoated strands or cords are given a mild heat treatment to set thetreating agent. A system of treatment for glass fibers may involve afirst surface treatment embodying an anchoring agent which enhances thebonding relationship between the glass fiber surface and the ultimatelyused elastomeric material. A suitable anchoring agent is represented bythe amino silanes such as gamma-aminopropyltriethoxy silane or by asimilar silane having a carboxyl group in the organic group attached tothe silicon atom or an amino or carboxyl group in the carboxylato groupof a Werner complex compound. These may be applied to the glass fibersurfaces or incorporated as a component of a size composition andapplied to the glass fibers as they are gathered together in theformation of strands, yarns or the like; all of which is more fullydescribed in the copending application Ser. No. 406,501 filed Oct. 26,1964 entitled, Glass Fibers Treated for Combination With ElastomericMaterials and Method. A desired strong bonding relationship can also beachieved by the impregnation of the strands or other multi-filamentglass fiber structure with a composition formulated to contain, inaddition, an elastomeric material, preferably in an uncured or anunvulcanized state as described in the aforesaid copending applicationSer. No. 406,501, as will hereinafter be illustrated by way of examples.

For purposes of comparison, the following table lists the reinforcementcord properties comparing glass cords with organic cords.

TABLE 2.REINFORCEMENT CORD PROPERTIES GLASS FIBERS VERSUS ORGANIC CORDSThe properties appearing in the foregoing Table 2 speak generally forthemselves. They generally demonstrate the toughness and impact strengthof glass fiber cords. This, coupled with their high dimensionalstability, demonstrates their great utility. Additionally, this, coupledwith their relatively inert character to temperature or humiditychanges, makes them a desirable and, in fact, an idealtire-reinforcement material when used in the manner disclosed herein.

The following are representative of size compositions which may beapplied to the glass fibers in forming.

Example I 0.5-2.0 percent by weight gamma-aminopropyltriethoxy silane0.30.6 percent by weight glycerine Remainder water Example II 8.0percent by weight partially dextrinized starch 1.8 percent by weighthydrogenated vegetable oil 0.4 percent by weight lauryl amine acetate(wetting agent) 0.2 percent by weight non-ionic emulsifying agent 1.0percent by weight glycylato chromic chloride- Example 111 3.2 percent byweight saturated polyester resin 0.1 percent by weight polargonate amidesolubilized with acetic acid 0.1 percent by weight tetraethylenepentamine stearic acid 0.1 percent by weight polyvinyl alcohol 3.0percent by weight polyvinyl pyrrolidone 0.3 percent by weightgamma-aminopropyltriethoxy silane 0.1 percent by weight acetic acid 93.1percent by weight water The size composition is merely applied to theglass fiber filaments as they are gathered together and the strand ofsized glass fibers is allowed to dry in ambient air.

In the foregoing examples, the gamma-aminopropyltriethoxy silane can bereplaced as an anchoring agent with other amino silanes such asgamma-aminopropylvinyldiethoxy silane,n(gamma-triethoxysilylpropyl)propylamine, beta-aminoallyltriethoxysilane, aniline silane derivatives, etc.

While it is not essential to impregnate the strand or bundle of glassfibers, it is preferred to impregnate the bundle of glass fibers forfuller separation of the fibers one from the other in the bundle and toincorporate an elastomeric system into the interior of the glass fiberbundle whereby the fibers can more effectively become anchored in theelastomeric system.

For this purpose, the strand or yarn of glass fibers is simply unwoundfrom a supply drum and advanced submergedly into a bath of theelastomeric impregnant. Thence, the impregnated yarn is pulled through awiping die which works the impregnating liquid into the intermostregions of the bundle or strand and also serves to wipe off excessmaterial.

The following are a few representative liquid compositions containing anelastomeric material which may be used to impregnate the bundle orstrand of glass fibers:

Example IV 100 parts by weight neoprene rubber 4 parts by weightpowdered magnesium oxide 5 parts by weight powdered zinc oxide parts byWeight Channel Black 1 part by weight Thiate B (trialkyl thioureaaccelerator) The foregoing ingredients after being mixed on a mill arecombined with sufficient of a suitable rubber solvent to form a liquidimpregnant bath.

Example V 100 parts by Weight Paracril C rubber (Buna N) parts by weightSRF carbon black 5 parts by weight powdered zinc oxide 6 0.5 part byweight Aminox (reaction product of diphenyl amine ester) 1 part byweight stearic acid 40 parts by weight dicumyl peroxide The foregoingingredients after being mixed on a mill are combined with sufficient ofa suitable rubber solvent to form a liquid impregnant bath.

Example VI 60 parts by weight Lotol 5440U.S. Rubber Company Lotol 5440is a 38% dispersed solids system including a butadiene-styrene-vinylpyridine terpolymer latex, a butadiene styrene latex and aresorcinol-formaldehyde resin.

39 parts by weight water Example VII 2 parts by weight resorcinolformaldehyde resin 1 part by weight Formalin (37% solution) 2.7 parts byweight concentrated ammonium hydroxide 25 parts by weight vinylpyridineterpolymer (42% latex) 41 parts by weight neoprene rubber latex (50%solids) 5 parts by weight butadiene latex (60% solids) .05 part byweight sodium hydroxide 1 part by weight gamma-aminopropyltriethoxysilane 1 part by weight vulcanizing agent 1100 parts by weight water Theimpregnated cord (multiple strand assemblies) are thereafter convertedinto a fabric by weaving technique or embedded in an elastomeric matrixby a combination creeling and calendering technique as illustratedschematically in FIG. 13 and more specifically described hereinafter.The woven impregnated cord fabric and/ or calender stock, each of whichis composed of mutually parallel cords of glass fiber strands, is thenbias cut in the case of incorporation into bias tires, or otherwise cutto appropriate size in the case of incorporation, as peripheral treadreinforcing belts (sometimes referred to as breaker strips), in radialtires. In either case, the fabric and/ or calendered stock containingthe mutually parallel cords is adapted to be incorporated inconventional tire building techniques.

Reference may now be had to the drawings wherein a number of tireconstructions in accordance with the present invention, as well as otherfeatures of novelty contemplated by the present invention, areillustrated. In FIG. 1, the reference numeral 20 identifies a 4-plybiastype tire. The tire is composed of spaced bead rings 22 and 24, eachof which includes a plurality of wire cords 25. Extending from bead'tohead are a plurality of carcass plies 26, 28, 30 and 32. Each of theplies is Wrapped about the bead ring, as illustrated in dotted line andin accordance with conventional practice. The plies 26, 28, 30 and 32are composed of impregnated cords composed of glass strands; the glassfilament components of which have been sized with one or the other ofthe sizes described in the foregoing Examples I-III. The cords aremutually parallel with cords in the same ply. The reference numeral 34aidentifies a rubber cushion ply making up the inner surface of the tire.A tread 33 extending peripherally about the crown portion of the carcassand a covering layer of rubber stock 34 in the side wall region oneither side completes the tire construction. The mutually parallel glasscords in ply 26 define an angle of about 38 with the peripheralcenterline 38 of the tread 33 of the tire. The cords in ply 28 areoppositely inclined from the cords in ply 26 and again define an angleof about 38 with the peripheral centerline. The cords in the ply 30 areparallel to the cords in the ply 26, while the cords in uppermost ply 32are parallel with the cords in ply 28. The angular disposition of thecords in the respective plies is most graphically illustrated in FIG. 2,particularly as to the relationship with the peripheral centerline 38which corresponds to the centermost groove in the tread 33. The cords inthe both hereinbefore and in more detail hereinafter.

bias ply may range from 27 to 38 with the peripheral center line.

FIGS. 3 and 4 illustrate a radial tire construction of the invention.The tire 40 is composed of spaced annular bead rings 42 and 44; each ofwhich contains a wire cord 45. The carcass is composed of a single ply47 including mutually parallel cords of glass strands. The individualcords are 90 disposed to the peripheral centerline 48. The ply 47extends from bead to bead and is turned up about the bead, asillustrated at reference numeral 49.- The reference numeral 56designates an inner cushion ply beneath the radial ply 47, whilereference numeral 51 identifies the tread which at the shoulder area 52joins the side wall 53 on each side as shown. The radial tireconstruction additionally includes reinforcing belts or bands 55 and 57between the radial ply 47 and the tread 51. These belts or hands aregenerally similar in construction to the radial ply 47; that is, theyare composed of a plurality of mutually parallel glass cords woven intoa fabric (the cords having been previously impregnated) or the cordsbeing embedded in a rubber matrix by the calendering technique referredto The reinforcing plies 55 and 57, however, extend from shoulder toshoulder, rather than completely from bead to bead.

'The reinforcing belt plies 55 and 57 are bias cut so that theindividual cords in the ply 55, for example, define an angle of about 18with the peripheral centerline 48 of the tire which corresponds with thecentermost groove of the tread 51. The cords in the uppermostreinforcing belt 57 are oppositely inclined to the cords in the belt 55to define an opposite angle of 18 with the peripheral centerline. SeeFIG. 4 for a more graphic illustration of the relationship of the cordsin the several plies.

A variant radial tire construction in accordance with the presentinvention is illustrated in FIGS. and 6. With but one departure, thetire illustrated in FIGS. 5 and 6 is the same as the tire illustrated inFIGS. 3 and 4 and accordingly the same reference numerals, but bearingthe subscript a, will be employed to designate the common parts. In thistire of FIGS. 5 and 6, the reinforcing band or belt 55 and 57 isreplaced by a single reinforcing belt 56. In this embodiment, the belt56 is bias cut in such fashion that the mutually parallel cords of glassstrands (many filaments) define an angle of 0 with the peripheralcenterline 48a.

In FIG. 7, there is shown a swatch 60 taken from a woven fabric suitablefor incorporation as a carcass ply or a reinforcing band or belt in anyof the tire constructions illustrated in the previous figures. Theswatch is taken from a woven textile composed of mutually parallel warpcords 62 secured together by a woof cotton pick 64 at spaced intervals.The cords 62 are composed of an assembly of strands, for example, 3;each of the latter including a -strand assembly. The ultimate cord, asshown, embodies a slight amount of twist for the purpose of overcomingany wildness which might be inherent in any opposite twist employed inassembling the lO-strand subassembly. A 3%. to 6" wide strip of thewoven fabric shown in FIG. 7 can be utilized to form the peripheralreinforcing band or belt 56 in the tire construction of FIG. 5. Thefabric 60 can also be used to form the radial ply 47 in the tireconstruction of FIG. 3. Continuous sheets, 55" wide, of this wovenconstruction can also be bias cut in accordance with conventional biascutting techniques to form the carcass plies 26, 28, and 32 in the tireconstruction of FIG. 1, or bias cut to form the reinforcing belts and 57in the construction of FIG. 3.

FIG. 8 illustrates a variant construction featuring sideby-side mutuallyparallel cords 70, each composed of an assembly of strands, each ofwhich is composed of a multiplicity of glass fibers. In this embodiment,the cords 70, seen in section, are embedded in an elastomeric matrix 71;the whole constituting a thin sheet. This construction, only a segmentof the sheet being shown in edge form in FIG. 8, may be produced by acombination of creeling and calendering, by laminating or other suitabletechniques, e.g., kiss coating, etc. With a multiple (45) roll calender,one pass will sufiice; while several passes will be necessary in a 3roll calender.

A tire construction embodying particularly desired features ofconstruction in accordance with the present invention is shown in FIG.9. The tire includes spaced bead rings, not shown, adapted to engage therim flange of a wheel, a tread-81 and a carcass therebeneath composed ofnylon bias plies 82 and 83 extending from bead to bead. The plies 82 and83 are oppositely inclined, as shown. In accordance with the presentinvention, the tire 89 includes, situated between the top carcass ply 83and the tread, a pair of reinforcing bands or belts 85 and 87. Both ofthe latter are composed of mutually parallel cords of glass in which theindividual cords define an angle of 24 with the peripheral centerline(corresponding with the centermost groove 89 in the tread 81). Themutually parallel cords in the reinforcing belts or plies 85 and 87 areoppositely inclined, one from the other, as shown. The bottornmostreinforcing belt 85 is slightly wider than the uppermost reinforcingbelt 87. In any event, they proceed completely about the periphery ofthe crown portion of the tire and their ends are either bias spliced orbutt spliced in conventional fashion. The plies 85 and 87 are preferablycompose-d of the mutually parallel cords embedded in an elastomericvulcanizable matrix, as shown in FIG. 8, having in mind ease of tirebuilding. The cords in the belt ply may range from 22 to 30 in angularrelationship with the peripheral center line although 24 is preferred.

FIG. 10 is a partial sectional view of the tire 80 of FIG. 9 and servesto better show the reinforcing belts or hands 85 and 87 as beingcomposed of the mutually parallel cords embedded in a vulcanizableelastomeric matrix.

FIG. 11 illustrates another preferred reinforcing system in accordancewith the present invention. The tire 90 is a retreaded tire; that is,the tire has been subjected to a retreading operation employingreinforcing bands or belts in accordance with the present invention. Inretreading, the tire is mounted in rotatable fashion and in inflatedcondition and the worn tread is accurately removed; care being taken notto injure the basic carcass plies, identified by the reference numerals91 and 92 in FIG. 11. These carcass plies may be rayon or nylon and inFIG. 11 are illustrated as a Z-ply bias tire. In accordance with thepresent invention, in the course of the retreading operation, there isemployed two reinforcing belts 94 and 95 which are composed of mutuallyparallel cords of glass strands. The belts extend generally fromshoulder to shoulder; the lowermost belt 94 being slightly wider thanthe uppermost belt 95. The reinforcing belts are bias cut and assembledon the crown so that the cords define a very slight angle of 7 with theperipheral centerline 97 of the tread 98. Retread tires employing thisconstruction under service conditions have been found to result inremarkable tread wear.

Impregnation of the glass cords (assembly of strands) is usuallyaccomplished by passing a continuous length of cord down into a pool ofthe impregnant solution or liquid (Examples IV-VII hereinabove listsuitable impregnant formulations) under conditions which tend to promotecomplete penetration of the impregnant liquid into the interstices orvoids, as it were, between filaments of glass making up the strand andthe cord. This may be done, for example, by causing the cord to passabout a peg while submerged, causing some distortion of the filamentstending to eliminate air from these interstitial voids and entrance ofthe liquid impregnant thoroughly about the individual fibers. A wipingdie through which the cord is passed after emerging from the impregnantbath also aids in thorough impregnation. Thereafter, the

cord is passed through a mild hot air oven sufficient to dry theimpregnant to a handleable non-tacky state. Care is taken in drying thatcuring is avoided. It is also possible to effect impregnation of thecords as a woven fabric. The components of the cord, e.g., the filamentsand strands, would, of course, be given a preliminary application ofsize after forming and/or during forming. Then the fabric made up ofmutually parallel cords may be passed into a reservoir or pool of theimpregnant in a manner similar to that described with the individualcord.

There will now be described several particularly desirable tireconstructions embodying preferred constructional features together withphysical test results and, as well, road test results closely simulatingactual service conditions.

Example VIII A number of 8.50 x 14 tubeless passenger tires wereproduced as described as follows. The tires were 4-ply bias-type tiresof the type illustrated in FIGS. 1 and 2. The glass cord employed infabricating the carcass plies is designated as ECG 150 10/0 1.5 S t.p.i.In this designation, E identifies an electrical glass; C identifies acontinuous filament; and G identifies the individual fiber diameter as0.00036 inch. The designation =150 Stands for 15,000 yards per poundnominal of basic strand. The designation 10/0 indicates that the cord iscomposed of 10 strands. The 1.5 S t.p.i. designates that in assemblingthe cord from the 10 strands there was imparted 1.5 S twists per inch. Acord has an S twist if, when it is held in the vertical position, thespirals around its central axis conform in direction of slope to thecentral portion of the letter S. It may be mentioned hereparenthetically that a Z twist is possible if the spirals referred toconform in direction of slope with the central portion of the letter Z.The cord was converted into a carcass fabric by drum winding the cord(pickless) so that the cords were in mutually parallel relationship,thence the cords transferred to a calender yielding a calendered fabrichaving mutually parallel cords therein in an amount numbering 24 cordends per inch. The calendered fabric measured 0.046 inch in thickness.The calendered glass cord carcass ply was bias cut at an angle of 26 toyield 4 plies having the following dimensions:

Width, inches Length, inches The carcass plies were combined into a tirebuilding operation in conventional fashion. The bead constructioncomprised layers of 5 wires each. The beads were wrapped with 1%" widestrip of 0.040 gauge stock. A flipper strip 2% wide was employed. As achafer, there was utilized 2% skim coated rayon multifilament, 20 x 20square woven. A 1%" gum strip was employed under the turnups in the tirebuilding operation. After application of the tread stock, the greentires were removed from the drums and vulcanized in a Bagamatic moldemploying internal temperature of 375 F. steam (170 p.s.i.) and anexternal temperature of 335 F. steam. These conditions were held for 21minutes. No post inflation was employed. The final tire weighed 30pounds. The resulting tires possessed a bias crown angle as cured of 38taken with respect to the peripheral centerline, e.g., the center grooveof the tread of the tire. The tires were subjected to road testing asfollows: 4 of the tires were mounted on a 1962 Chrysler. The tires wereinflated to 28 p.s.i. and the loading was adjusted to 1180- 1190 poundsper tire. The road test continued for 24 hours daily on a five-day cycleat 1125 miles per day. The road surface involved was granulated macadamand concrete. The speed of the vehicle was maintained at miles per hour.The test road was 385 miles long, in cluding 88 miles of sharp curves,dips and hills, 42 miles of rounding curves and hills, and 255 miles ofstraight road. The tires were examined after completing 20,250 miles.The original tires in a plunger test with a threequarter inch probeyielded a value of 5190 pounds, A comparative 4 bias ply carcass nylontire tested 3948 pounds. The tires were rotated, each 1125 miles, byputting the front tires straight back while the rear tires werecrisscrossed to the front. The tread depth was measured periodically.After 20,250 miles, the tread depth of four tires revealed the followingmiles per mil of tread wear, e.g., (miles/.001): 1'36, 155, 141 and 162.Identical tires subjected to the same road test but at an inflation of32 p.s.i. yielded the following tread wear values for the four tires inmiles per mil (miles/ .001): 147, 146, 139 and 148. Extrapolation of thetread wear data at the 20,250 mile yielded an estimated ultimate mileageof 53,000 miles. The 28 p.s.i. inflated tires were then subjected tocontinued road testing on the same test road until a mileage of 43,000miles. The tread wear for the tires in miles per mil (miles/ .001)ranged from 118 to 140.

The tires at this point were removed from the car and recapped, thenremounted on the car and run to from 48,000 to 51,500 miles. One of thetires at a mileage of 47,250 miles was removed and the tire cord wasseparated from the tire by dissolving in a hot DoWtherm E solvent. Thecord was then subjected to radiographic analysis which revealed the cordto be continuous, e.g., no broken cord or fiber. The original tires asvulcanized revealed an embedded cord breaking strength of pounds. Thefinal 47,250 mile tire, upon removal of the cord, was subjected to anembedded breaking strength yielding a value of 60 pounds. The final worntires, upon examination of the grooved depth, revealed a tread wear inmiles per mil of 140 to 153. Under the conditions of the test, the testreport revealed that the stability of the tires was very good with norollover or sway on curves. The tires were reported to grip the roadwell in wet weather. The general appearance of the tire at 43,000 mileswas reported very good. No natural cracking developed throughout thetest. Stone cutting in the grooves was reported as very slight.

Example IX A number of radial type tires, as generally illustrated inFIGS. 3 and 4 of the drawings, were built and road tested as follows:The tires were 135 x 380 tubeless type tires. The carcass was composedof a single radial ply and a double ply restrictive belt locatedcircumferentially about the single radial ply and extendingsubstantially from shoulder to shoulder. The glass cord utilized infabricating the carcass and restrictive belt plies is designated a G10/3 1.5 t.p.i. cord. The G identifies a basic glass filament diameterof 0.00036 inch in diameter. The

-l50 designates 15,000 yards per pound of the basic strand. The 10/ 3designates that there was first prepared a 10-strand assembly employinga 2.5 Z uptwist. Three of the latter were then combined to form thecord, using a 1.5 S twist per inch in the assembly of the threel0-strand yarns. The cord was thence impregnated in the manner describedhereinbefore and thence woven into a fabric featuring a warpedconstruction featuring 16 ends per inch of the cords and a filling yarncomposed of 3 picks per inch of a 50/2 cotton yarn. The 16 end per inchglass cord fabric with the 3 cotton picks was combned with rubber stockon a calender set to yield a calendered fabric having a gauge of 0.049inch. This fabric was cut to appropriate size and utilized as the radialcarcass ply in which the individual cords proceeded from head to bead atan angle of 90 with the peripheral centerline of the cured tire.Additional amounts of the same glass cord calendered fabric wasutilized, that is, bias cut in such fashion that, when applied as arestrictive band or belt, the cured tire revealed a bias belt or bandbias angle of 18 between the cords and the peripheral centerline of thetire. The cords in the two bands were oppositely inclined for dynamicstability. The ultimately vulcanized tires were road tested by mountingon a Falcon under a load condition of 725 pounds per tire. The rim uponwhich the tire was mounted was a 4" rim. The road testing involved aprimary road 425 miles; such being traversed in an 8-hour shift. Maximumspeeds of 60-65 miles per hour were maintained for at least 90% of thecycle. The tires were inflated to 26 psi. The test was continued for a6-day cycle in which the weather was clear and the road surface wasmacadarn. The load of 725 pounds per tire represents a 30% overloadbased on a 555 pound maximum load according to Michelin specification atan inflation pressure of 20 p.s.i. The tires ran for a total of 44,400miles, at which time the test was discontinued with tread remaining ontwo of the tires. The Wear characteristic upon measurement wasdetermined to be 262 miles per mil. By comparison, a comparable sizetire, e.g., a 6.50 X 13 2-ply bias tire, tested under the same'speed andload conditions yielded an average mile per mil value offrom 90100.Measurement of the tread depth of the two road tested tires having treadremaining if extrapolated gives an estimated miles to smoothness valuein the order of 70,000 miles. Measurement of the test tires over theduration of the test period as to average height and width sectiondimensions yielded a percent range in the range of 0.2% and 0.3%,respectively, from original tire dimensions. Visual observation of thetest tires revealed a qualitatively flatter profile and footprint thanother conventional radial design tires. One of the original tires failedto last the 44,400 mile duration, but instead failed at 40,158 miles.Examination revealed side wall rubber cracking. X-ray examinationclearly indicated the cord to be in satisfactory condition.

Example X complement the two bias nylon plies and lend stability to theultimate tread in accordance with this invention, the tire constructionWas modified to include a pair of reinforcing belts containing mutuallyparallel cords of glass (assembly of strands) utilizing a calenderedfabric construction as described hereinbefore in Example VIII. The beltswere assembled onto the crown portion of the carcass prior to applyingthe tread in such fashion that the cords in the belt plies measured anangle of 24 with the peripheral centerline of the tire, as shown in FIG.9. The belts were applied so that the cords in each 'Were oppositelyinclined. One tire, which road tested 11,550 miles on a Chrysler atspeeds of 50-70 miles per hour at a cold inflation of 28 p.s.i.,revealed a tread wear at the centerline of 140 miles per mil. Anothertire so constructed, after 6,930 miles, revealed a wear at thecenterline of 145 miles per mil. In contrast, two 4-ply nylon controltires over 12,705 and 12,380 mile tests revealed a wear, respectively,of 84 miles per mil and 87 miles per mil. Tires constructed inaccordance with this example, namely, employing two nylon bias carcassplies and reinforcing belts formed of calendered glass cord, represent apreferred embodiment of the present invention, inasmuch as the ultimatetire appears to possess the tread wear and stability characteristics ofa radially designed tire of the Michelin type, yet it is capable ofbeing constructed on existing tire building equipment of theconventional bias type.

the of bead wires 105.

12. Example X! To demonstrate the applicability of the reinforcingsystem of the present invention in retreading operations, twoconventional tires were retreaded, but incorporating, under the treadand over the crown portion of the rayon bias carcass plies, two layersof a glass cord fabric bias cut to yield a cord angle of 7 with theperipheral centerline of the tire when ultimately vulcanized. Thelowermost layer belt or tape was 4" wide and the uppermcst belt was 3 /2wide. The belt fabric was a calendered assembly in which the cordcontent measured 20 ends per inch. The cords, of course, had beenpreviously impregnated. These two tires retreaded with the two glasscord breaker plies were mounted on a taxi together with two conventionalretreads as controls. .After running 3,000 miles, the tires weretransferred to a 1963 Chrysler driven at 65 miles per hour on theLouisville to Indianapolis Turnpike. The tires were checked and rotatedevery 525 miles. At the end of 2,075 miles of turnpike testing, thecontrol tires measured a tread wear of 61 miles per mil, whereas thetires of the invention measured miles per mil (average). The tires wereremoved and subjected to a southwestern Texas control road test whereinthe speed was held between 60 70 miles per hour at an inflation of 24psi. cold. The tires were rotated front straight back with the reartires crisscrossed to the front, each 1155 miies. One of the tires ofthe invention failed at this road test at 6612 miles or a total mileageof 11,715 miles. An observation revealed that the failure was due to aside wall snap, rather than to a carcass weakness. This tire revealed atread wear of 116 miles per mil. The other tire of the invention ran to14,343 miles and revealed a tread wear of 91 miles per mil at thecenterline. One of the control tires was smooth at the completion of the14,343 miles total, while the other tire, though not smooth, measured atread wear of 52 miles per mil at the centerline.

The reinforcing band or belt composed of an elastomeric matrix havingembedded therein a spaced plurality of mutually parallel glass cordrepresents a particularly desired feature of the present invention sinceit is readily adapted into present tire buiding operations and lendsgreatly improved tread stability. The material in sheet form as producedon a calender or the like may be bias cut and further processed andhandled as conventional organic textile fabrics. Viewed in section as,for example, in FIG. 8, it may be seen that the rubber component, on avolume basis, is about equal to that of the glass. In section, thisrelationship appears as one of area comparisons between the sectionalportion indicating elastomer and the circles representing the cords inmutually parallel relationship. A volume ratio of elastomeric matrix toglass providing improved tread stabilizing properties falls within therange of from about 1.0/1.0 to about 3.0/1.0. Where the amount of glassexceeds the rubber on a volume basis, the strength retention decreasesand, consequently, its ability to lend tread stability and generalreinforcement is not as desirable as where the volume ratio of rubber toglass is within the prescribed ratio set forth hereinabove.

In FIG. 12, there is illustrated a tire 101 embodying further featuresof construction in accordance with our invention. The tire 101 is notshown in detail as to the carcass plies, but may include a carcassconstruction and also may include reinforcing belts as illustrated inthe constructions illustrated in earlier figures. The tire in generalincludes spaced beads 103 and 104 and a ground contacting tread 102. Thehead member includes a bun- To reduce the tendency of the individualwires to become separated, the rubber stock in the region surroundingthe bead wires is stiffened or toughened to reduce the flowcharacteristics by including a phenolic resin, a resorcinol formaldehydelatex or an epoxide coating. In place of the wires, we may use cords ofglass as described earlier herein; care being taken to include animpregnant precluding fiber contact with adjacent fibers. Alternativelyor additively, the bead elements are reinforced by a spiral wrap member106 which is wound about the bead wire assembly. The wrap is preferably,in accordance with the present invention, composed of a cord of glassfiber strand assemblies impregnated in a manner described hereinbefore.The wrap cord of glass fiber strands can be further encapsulated, as itwere, in a thermosetting resin such as an epoxy resin, a phenolic resinor a resorcinol formaldehyde latex composition.

FIGS. 13 and 14 are, respectively, a schematic side elevation view and aschematic top plan view of an apparatus setup adapted to convert glasscords int-o calendered stock containing mutually parallel cords of glassembedded therein. As indicated hereinbefore, the apparatus involvedconsists of a combination of creeling and calendering apparatus. As increeling, an array of rotatable spools 201 are provided, each containinga continuous length of the preferably previously impregnated cord woundthereon. Only six spools 201 are shown; it being understood that, toproduce a 55" wide continuous length of the calendered stock, up to1,000 or more spools may be involved, considering a cord spacing varyingfrom to 30 ends per inch of the 55" width. The array of cords 202 ispassed over a comb or reed 23 which arranges the cords into mutuallyparallel relationship and also spaced as to provide from 10 to 30 e.p.i.(ends per inch). The cords C thence pass between principal opposedcounterrotating rolls 206 and 207 of a 4-roll calender setup, whereinthe cords are embedded in elastomeric stock. The rubber stock is fedinto the nip between principal calender roll 206 and a counterrotatingfeed roll 208. The stock is also fed into the nip between principallower calender roll 207 and a counterrotating feed roll 209. Thecalenders 206 and 207 are spaced apart a distance corresponding to thedesired gauge of the final product 210. The calendered stock 210 isthence passed to a take-off conveyor 211. Although not shown, it issometimes desirable to employ tension rolls on the delivery side of thecalender rolls in order to pull the product through the calendered setup206 and 207 in a uniform manner.

It will be appreciated that variations in constructional features, aswell as substitution of equivalent components, may be undertaken withoutdeparting from the spirit and scope of the present invention, and allsuch obvious equivalents and substitutes are intended to be coveredunless specifically excluded by the scope of the appended claims.

We claim:

1. In a tire construction comprising two spaced annular heads, atoroidal carcass connecting said beads and an outer peripheral treadsupported by said carcass, the improvement which includes a plurality ofbias plies defining said carcass and extending from bead to bead, saidplies each including a plurality of mutually parallel cords eachcomposed of a plurality of essentially continuous glass fibers assembledtogether, said cords defining a bias angle with the circumferentialcenterline of the tire ranging from 27-3 8", said cords each beingembedded in an elastomeric matrix substantially percluding contactbetween adjacent cords, said elastomeric matrix and glass being presentin a relative volume ratio ranging from at least about 1.0/1.0 to notmore than 3.0/1.0.

2. A tire construction as claimed in claim 1 wherein said cords are of aconstnuction characterized as ECG 150 10/0 1.5 t.p.i. wherein Eidentifies an electrical glass, C identifies a continuous filament, thenumeral 150 stands for 15,000 yards per pound of basic strand, thenumeral 10/0 identifies 1a IO-stranvd cord and the designation 1.5 St.p.i. identifies the 1.5 S twist per inch imparted to the 10 strands inassembling the cord.

3. A tire construction including spaced beads, a connecting carcass, anouter ground engaging tread, said carcass including at least two biasplies extending from head to bead, said bias plies including parallelcords formed of organic fibers, and a pair of belt-like reinforcingmembers peripherally encircling said carcass beneath said tread, saidbelts each being composed of mutually parallel cords composed of aplurality of assembled strands of substantially continuous glassfilaments, said parallel cords describing an angle of 22-30 with theperipheral centerline of the tire, said cords in the adjacent beltsbeing oppositely inclined.

4. A tire construction as claimed in claim 3 wherein said mutuallyparallel cords in said pair of belts are embedded in an elastomericmatrix and spaced apart sufiiciently to provide about 1030 cord ends perlineal inch on a line normal to said cords.

'5. A tire construction as claimed in claim 4 where the number of cordends ranges from about 20 to 24.

6. A tire construction as claimed in claim 4 wherein the belts measureabout 0.046 inch in thickness.

7. A tire construction as claimed in claim 4 wherein said cords are of aconstruction cha-nacterized as ECG 10/0 1.5 t.p.i. wherein E identifiesan electrical glass, C identifies a continuous filament, the numeral 150stands for 15,000 yards per pound of basic strand, the numeral 1 0/0identifies a 10-strand cord and the designation "1.5 S t.p.i. identifiesthe 1.5 S twists per inch imparted to the 10 strands in assembling thecord.

8. A tire construction as claimed in claim 4, wherein the volume ratioof elastomeric substance to glass as viewed in section ranges from about1.0:1.0 to about 3.0:1.0.

9. A tire construction as claimed in claim 8, wherein the said volumeratio is about 1.0.

10. A tire construction including spaced beads, a connecting carcass, anouter ground engaging tread, said carcass including at least two biasplies extending from bead to bead, said bias plies including parallelcords formed of organic fibers, and a pair of belt-like reinforcingmembers peripherally encircling said carcass beneath sai-d tread, saidbelts each being composed of mutually parallel cords composed of aplurality of assembled strands of substantially continuous glassfilaments, said parallel cords describing an angle of 24 with theperipheral centerline of the tire, said cords in the adjacent beltsbeing oppositely inclined.

11. An elastomeric tire construction including spaced parallel beadrings, a carcass connecting said beads and a peripheral groundcontacting tread portion secured to said carcass, said carcasscomprising closely spaced, parallel cords in radial disposition andextending from bead ring to bead ring, said cords consisting ofassembled strands of a plurality of essentially continuous glass fibers,said cords being separated by an elastomeric impregnant, said cordsnumbering about 10-30 ends per inch on a line normal to said cords, anda tread reinforcing band peripherally surrounding said carcass andsubstantially beneath said tread, said band comprising a plurality ofsaid cords.

12. An elastomeric tire construction including spaced parallel beadrings, a toroidal carcass connecting said beads and a peripheral groundcontacting tread portion secured to said carcass, said carcasscomprising closely spaced, parallel cords radially disposed andextending from bead ring to head ring, said cords consisting ofassembled strands of a plurality of essentially continuous glass fibers,sa-i-d cords being separated by an elastomeric impregnant vulcanizablycompatible with said elastomer, said cords numbering about 10-30 endsper inch on a line normal to said cords, and a tread reinforcing bandperipherally surrounding said carcass and substantially beneath saidtread, said band comprising a plurality of said cords situated generallynormal to the cords in said carcass, said band including a matriximpregnant 15 substantially surrounding the fibers in said cord, therebyprecluding contact therebetween.

13. A tire construction including spaced parallel bead members, atoroidal carcass connecting said beads, and a ground engaging treadportion of annular configuration peripherally secured to said carcass,said carcass including a plurality of closely spaced parallel bundles orcords of essentially continuous glass fibers assembled together, animpregnant substance surrounding said individual fibers, said bundles orcords describing a 90 angle with the peripheral centerline of said tire,said bundles or cords extending from bead to bead and terminating in areverse fold turn-up portion about said beads, a pluenality of bandmembers extending about said tire peripherally between the carcass andsaid tread portion, said band members including a plurality of bundlesor cords of essentially continuous glass fibers assembled together, saidband member cords in adjacent bands being equally but oppositelyinclined with respect to the peripheral centerline of the tread andconstituting an angle ranging from 10.

14. A retread tire construction as claimed in claim 13.

15. A tire construction including spaced parallel bead members, atoroidal carcass connecting said beads, and a ground engaging treadportion of annular configuration peripherally secured to said carcass,said carcass including a plurality of closely spaced parallel bundles orcords of glass fibers assembled together, an elastomeric impregnantsubstance surrounding said individual fibers, said bundles or cordsdescribing a 90 angle with the peripheral centerline of said tire, saidbundles or cords extending from bead to bead and terminating in areverse fold turn-up portion about said beads, a plurality of bandmembers extending about said titre periphelna'lly between the carcassand said tread portion, said band members including a plurality ofbundles or cords of glass fibers assembled together, said band membercords in adjacent bands being equally but oppositely inclined 16 atabout 18 degrees with respect to the peripheral centerline of the tread.

16. A tire construction as claimed in claim 15 wherein said cords arespaced apart sufiiciently to provide about 16 cord ends per inch on aline normal to said cords.

17. A reinforcing band or belt for incorporation into tire construction,said band comprising (a) cords composed of strands of essentiallycontinuous glass fibers and (b) an elastomeric matrix in which saidcords are embedded in closely spaced, mutually parallel relationshipmeasuring from 10-30 cord ends per inch, said band exhibiting as viewedin section a volume ratio of elastomeric matrix/glass ranging from1.0110 to 30:10.

18. A reinforcing band as claimed in claim 17, wherein said cord spacingis such as to provide 10 to 30 cor ends per inch on a line normal tosaid cords.

19. A meinfoncing band as claimed in claim 18, wherein the number ofcord ends ranges from about 20 to 24 cord ends per inch.

20. A reinforcing band as claimed in claim 19, wherein said volume ratioof elastomeric matrix to glass is about 1.0 to 1.0.

References Cited by the Examiner UNITED STATES PATENTS 2,184,326 12/1939Thomas 152-358 2,224,274 12/1940 Powers 152-359 X 2,827,099 3/1958Youngs 152359 2,884,040 4/ 1959 Boussu et al 152-36l X 2,894,555 7/1959Bourdon 152-361 2,930,426 3/1960 Klang et al. 152361 2,960,139 11/1960Engstrom et al. 152-354 3,077,915 2/1963 Weber 152--355 3,106,952 10/1963 Rudder 152-362 ARTHUR L. LA POINT, Primary Examiner.

C. W. HAEFELE, Assistant Examiner.

1. IN A TIRE CONSTRUCTION COMPRISING TWO SPACED ANNULAR BEADS, A TOROIDAL CARCASS CONNECTING SAID BEADS AND AN OUTER PERIPHERAL TREAD SUPPORTED BY SAID CARCASS, THE IMPROVEMENT WHICH INCLUDES A PLURALITY OF BIAS PLIES, DEFINING SAID CARCASS AND EXTENDING FROM BEAD TO BEAD, SAID PLIES EACH INCLUDING A PLURALITY OF MUTALLY PARALLEL CORDS EACH COMPOSED OF A PLURALITY OF ESSENTIALLY CONTINUOUS GLASS FIBERS ASSEMBLED TOGETHER, SAID CORDS DEFINING A BIAS ANGLE WITH THE CIRCUMFERENTIAL CENTERLINE OF THE TIRE RANGING FROM 27-38*, SAID CORDS EACH BEING EMBEDDED IN AN ELASTOMERIC MATRIX SUBSTANTIALLY PERCLUDING CONTACT BETWEEN ADJACENT CORDS, SAID ELASTOMERIC MATRIX AND GLASS BEING PRESENT IN A RELATIVE VOLUME RATIO RANGING FROM AT LEAST ABOUT 1.0/1.0 TO NOT MORE THAN 3.0/1.0. 